Zarrouk Medium Research Articles

Nutrient balance for enhanced recovery of stressed Spirulina platensis.

The failure of mass production of Spirulina plateaus can be attributed to an imbalance of nutrients (C:N) and an increase in accumulated sodium ions, coupled with the traditional harvesting process. The current study aims at the recovery of stressed and red cultures of Spirulina platensis as well as enhanced phycocyanin accumulation. The stressed Spirulina platensis cultures were obtained from a local Egyptian Spirulina production farms, which were further subjected to water analyses after removing the Spirulina biomass. Optimization was performed within 300-ml water path photobioreactor. Spirulina platensis samples were incubated with Zarrouk medium comparing with those modified using ammonium bicarbonate or ammonium acetate instead of sodium bicarbonate. Continuous batching was performed every 12days during three sequenced batches. Growth measurements (dry weight and pigments) were performed along the incubation time. It was found that carbon content of the growth medium seems to be more effective in Spirulina growth and biomass characteristics. Under different carbon sources, acetate resulted in the maximum dry weight of 1.48g·l-1 and recovery percentage of 463.3%. Such effect was extended along the different incubation batches. Various carbon concentrations revealed that moderate concentration of carbon in the form of acetate (0.699g·l-1) leads to the maximum growth under the same nitrogen content. A similar trend was observed with chlorophyll and phycocyanin accumulation, while carotenoids showed the opposite manner.

Analytically monitored cultivation of Arthrospira platensis on food waste extracts to compose a sustainable, low-prized, Zarrouk-based medium

ABSTRACT A sustainable, low-cost medium based on food waste for cultivating the cyanobacterium Arthrospira platensis (A. platensis) was investigated. Zarrouk medium components, especially phosphate, were substituted with extracts from beetroot peel, brewer’s grains, and walnut press cake. Ion concentrations of magnesium, calcium, iron, potassium, sodium, phos-phate, nitrate, sulfate, and chloride were analyzed to determine the optimal medium composition. Walnut press cake and brewer’s grains extracts showed high potential due to their magnesium, calcium, and phosphate content. Brewer’s grains extracts also provided glucose as an additional carbon source. Cultivations in shaking flasks and a photobioreactor (PBR) monitored cell growth through optical density and biomass concentration. The excess of magnesium and reduced phos-phate concentrations positively affected biomass production. A. platensis’s ability to metabolize glucose resulted in 68% higher biomass production. Growth in brewer’s grains extract required no additional phosphate. PBR cultivation showed A. platensis consumed significant magnesium and nitrate, achieving higher biomass concentrations with optimized gas exchange and light reflection systems.

Combined effect of LED light color and nitrogen source on growth, pigments composition and oxidative stress in Arthrospira platensis

Artificial lighting with light-emitting diodes (LED) is proposed as a suitable solution to reach stable yearly production of high value molecules from microalgae under unfavorable climates. However, available studies are inconsistent regarding the effect of LED color on cultures performance. This study examined the response of Arthrospira platensis to three different LED lighting conditions (white, red, and red-blue 70:30) when is grown in three media with different nitrogen composition. Growth, phycobiliproteins and lipophilic pigments content were determined. In addition, antioxidant enzymes (GST, lipid peroxidation) and morphology were analyzed to enlighten new perspectives on the health status of microalgae production.The highest biomass production (2.13 g/L) was achieved under red LED when Zarrouk medium was supplemented with urea. Regarding pigment production (phycobilins, chlorophyll a and β- carotene), the most desirable combination was red: blue together with urea supplementation. In addition, this combination showed a high biomass production (2.03 g/L) and low expression of antioxidant enzymatic activity. This research shows a novel combination of LED technology and nutrients to enhance microalgae biomass production and high value metabolites with a lower economic cost.

Cradle-to-gate life cycle assessment of Spirulina bioplastic produced via plasticization with glycerol

Bioplastics have been used as alternatives to conventional petroleum-based plastics to lessen the burdens on marine and terrestrial environments due to their non-biodegradability and toxicity. However, recent studies have shown that not all bioplastics may be environmentally friendly. Microalgae, such as Spirulina that do not require arable land, have been identified as a potential bioplastic source. In this study, cradle-to-gate life cycle assessment (LCA) was carried out in openLCA program using the Agribalyse database, to evaluate the environmental impacts of Spirulina bioplastic, formed from plasticization of Spirulina powder with glycerol. Two processes were created for the inventories of (i) Spirulina powder and (ii) Spirulina bioplastic, where the output of the former served as an input for the latter. The extruded bioplastic sheets were food-grade and could be used as edible packaging materials. The bioplastic was also compared to conventional plastics and it was found that the energy consumption was 3.83 ± 0.26 MJ/kg-bioplastic, which was 12% and 22% higher than that of LDPE and PVC plastic films, respectively. The impacts on the environment showed that the chemical growth medium (Zarrouk medium) and electricity were the main contributors in most of the categories. Compared to the PVC and LDPE films, the Spirulina bioplastic's impacts on the aquatic ecosystems were 2–3 times higher. The global warming potential of the Spirulina bioplastic was 1.99 ± 0.014 kg CO2 eq, which was 23% and 47% lower than that of LDPE and PVC films, respectively. Sensitivity analysis was carried out by changing the electricity source and using alternative growth media. Except for the case of switching to solar energy, the results for other cases did not differ significantly from the base case scenario. Future studies were suggested to identify different greener alternatives to the growth medium as well as different energy mixes for more environmentally benign solutions.

New nutrients evaluation in Spirulina maxima growth for phycocyanin, carbohydrate, and biochar production

Purpose The purpose of this study is to investigate the influence of light intensity and sources of carbon and nitrogen on the cultivation of Spirulina maxima. Design/methodology/approach Cultures were carried out in a modified Zarrouk medium using urea, sodium acetate and glycerol. A Taguchi experimental design was used to evaluate the effect on the production of biocompounds: productivities in biomass, carbohydrates, phycocyanin and biochar were analyzed. Findings Statistical data analysis revealed that light intensity and sodium acetate concentration were the most important factors, being significant in three of the four response variables studied. The highest productivities in biomass (46.94 mg.L−1.d−1), carbohydrates (6.11 mg.L−1.d−1), phycocyanin (3.62 mg.L−1.d−1) and biochar (22, 48 mg.L−1.d−1) were achieved in experiment 4 of the Taguchi matrix, highlighting as the ideal condition for the production of biomass, carbohydrates and phycocyanin. Practical implications Sodium acetate and urea can be considered, respectively, as potential sources of carbon and nitrogen to increase Spirulina maxima productivity. From the results, an optimized cultivation condition for the sustainable production of bioproducts was obtained. Originality/value This work focuses on the study of the influence of light intensity and the use of alternative sources of nitrogen and carbon on the growth of Spirulina maxima, as well as on the influence on the productivity of biomass and biocompounds. There are few studies in the literature focused on the phycocyanin production from microalgae, justifying the need to deepen the subject.

Continuous cultivation of microalgae yields high nutrient recovery from nitrified urine with limited supplementation

Microalgae can play a key role in the bioeconomy, particularly in combination with the valorisation of waste streams as cultivation media. Urine is an example of a widely available nutrient-rich waste stream, and alkaline stabilization and subsequent full nitrification in a bioreactor yields a stable nitrate-rich solution. In this study, such nitrified urine served as a culture medium for the edible microalga Limnospira indica. In batch cultivation, nitrified urine without additional supplements yielded a lower biomass concentration, nutrient uptake and protein content compared to modified Zarrouk medium, as standard medium. To enhance the nitrogen uptake efficiency and biomass production, nitrified urine was supplemented with potentially limiting elements. Limited amounts of phosphorus (36 mg L−1), magnesium (7.9 mg L−1), calcium (12.2 mg L−1), iron (2.0 mg L−1) and EDTA (88.5 mg Na2-EDTA.2H2O L−1) rendered the nitrified urine matrix as effective as modified Zarrouk medium in terms of biomass production (OD750 of 1.2), nutrient uptake (130 mg N L−1) and protein yield (47%) in batch culture. Urine precipitates formed by alkalinisation could in principle supply enough phosphorus, calcium and magnesium, requiring only external addition of iron, EDTA and inorganic carbon. Subsequently, the suitability of supplemented nitrified urine as a culture medium was confirmed in continuous Limnospira cultivation in a CSTR photobioreactor. This qualifies nitrified urine as a valuable and sustainable microalgae growth medium, thereby creating novel nutrient loops on Earth and in Space, i.e., in regenerative life support systems for human deep-space missions.

Optimization of Chelating Process of Amino Acids of Leather Waste and Glycine with Different Minerals and Its Relationship with Arthrospira platensis Biological Activities

There are several factors were taken in consideration such as time, ratio, temperature and pH to improve the chelation process between the amino acids and inorganic ions. The current study aims to optimize the physical factors controlling the synthesis of chelated amino acids with different minerals and to enhance antioxidant and biodiesel production from Arthrospira platensis cultivated in culture enriched with different chelated minerals. In this study; various physical factors such as (ratio of amino acids and minerals; temperature, time and pH) were used for optimization of chelation formation. The blue -green alga Arthrospira platensis was cultivated under different synthesized chelated minerals (T1-T13), the growth rate, antioxidant, antiradical and biodiesel production were determined in all treated alga. The obtained results showed that the optimum conditions for production of chelated amino acid were ratio (2:1 M), temperature at 60 °C, the duration between 4:5 days and the suitable or stability of chelation at pH = 4, Also, the growth rate of A. platensis with Cu-glycinate higher than Cu-leather waste and Zarrouk media. The antioxidant activity results of different extracts of Arthrospira platensis showed that the water extract gave high antioxidant activity against DPPH radical assay than acetone extract in all treatments when compared with untreated culture (Zarrouk’s medium). Arthrospira platensis cultivated on Zarrouk medium supplemented with chelated amino acids with metals was showed an increase in algal pigments and lipids with Mn-LW, Zn-LW and Mg-LW treatments. Also, the results showed that the produced biodiesel was observed with M-LW treatments, which was more than that of glycinate treatments, untreated culture (Zarrouk) and LW biodiesel. Therefore, the highest biodiesel percentages were founded with Zn, Mn and Mg-LW (5.37, 5.25 and 4.86% respectively). The recorded results and material balance data concluded that possibility for use the chelated minerals (glycine and leather wastes) as plant fertilizer in future because its high yield and low fees for production.Graphical

EFFECTS OF VARIOUS LIGHT INTENSITIES ON PHYCOCYANIN COMPOSITION OF CYANOBACTERIUM LIMNOSPIRA FUSIFORMIS (VORONICHIN) NOWICKA-KRAWCZYK, MÜHLSTEINOVÁ & HAUER

Phycocyanin denotes a photosynthetic pigment discovered in Rhodophyta and cyanobacteria, which has been used in medical, industrial, and agricultural applications. In general, phycocyanin production by cyanobacteria depends on many environmental conditions, mainly light during the cultivation period. The goal of this research was to see how various light intensities of 47, 52, as well as 60 µmol m-2 s-1, affected the Phycocyanin production of cyanobacterium Limnospira fusiformis cultured in Zarrouk medium with a maximum temperature of 28°C. The outcomes revealed that with mild light intensity (52 µmol m-2 s-1), increased phycocyanin production of 11.94 ng/mg took place. With regard to greater light intensity (60 µmol m-2 s-1), the lesser phycocyanin production of 0.57 ng/mg took place. These results give a good impression that moderate lighting increases phycocyanin production, but high light intensity inhibits it. The statistical analysis results also showed that there are significant differences between the light intensities used in the study at a level of p<0.05. Therefore, this study concluded that phycocyanin was affected by light intensity. Light regime optimization gives a good yield of this pigment. In this study, high phycocyanin production by cyanobacterium Limnospira fusiformis occurred in mild light intensity (52 µmol m-2 s-1).

The Influence of Ultrasound on the Growth of Nannochloris sp. in Modified Growth Medium.

The influence of ultrasound irradiation on the algal biomass productivity as well as its oil content and fatty acids profile, grown in a modified Zarrouk medium, i.e., deproteinized whey waste solution, was investigated. The algal samples (Nannochloris sp. 424-1 microalgae) were grown for 7 days in a thermostated incubator at 28 °C, shaken under continuous light. During this period, the algal biomass was subjected to induced stress by ultrasonic irradiation at different powers and sonication time. The obtained results demonstrate that ultrasound stressing of algae biomass has a positive effect on both the quantity of biomass and the oil obtained, also causing a shift in fatty acid composition by increasing the proportion of C16 and C18 polyunsaturated fatty acids. A low dosage level of exposure to the ultrasound led to algal biomass increase as well as lipid accumulation. For both types of irradiation modes which were investigated, daily and only initial irradiation, the beneficial effect of the ultrasound decreases as the exposure time increases and the excessive sonication becomes detrimental to microalgae growth.

Optimization of Chlorella vulgaris cultivation grown in waste molasses syrup using mixture design

AbstractThe aim of this study was to determine and optimize culture media for Chlorella vulgaris microalgae under mixotrophic conditions using waste molasses as a cheap carbon source containing both organic carbons and other nutrients. In the current study, at first the growth and lipid productivity of C. vulgaris were assessed in different culture media and the best media was selected for mixotrophic growth conditions. Significant medium ingredients were screened through Plackett–Burman design. Then ingredients with positive effect were considered as a mixture component and their combinations were evaluated on lipid productivity using mixture design. According to results, Zarrouk medium was considered as the base medium with the highest biomass and lipid productivity of 72 and 7.1 mg L−1 d−1, respectively. Based on the Plackett–Burman design, out of 11 factors, molasses, NaNO3 and K2HPO4 demonstrated key roles in biomass and lipid productivity in mixotrophic conditions. Consequently, the selected three factors were investigated by mixture design. The results showed that high concentration of molasses causes decrease in biomass and lipid productivity due to high turbidity and a blend consisting of approximately 9.5 g L−1 molasses, 5 g L−1 NaNO3 and 0.15 g L−1 K2HPO4 was found as the optimum mixture with obtained lipid productivity of 115 mg L−1 d−1. In conclusion, waste molasses can be used as a promising feedstock for cost effective cultivation of C. vulgaris.

Biotechnological studies on Arthrospira platensis biomass cultivated in enriched culture with chelated leather waste and chelated glycinate

The current work aims to evaluate the growth rate, molecular patterns and biological activities of Arthrospira platensis cultivated in culture enriched with different chelated minerals (Fe, Zn, Cu, Mn, and Mg) of leather protein hydrolysates (LPHs) and glycine in addition to determine the phytochemical contents of Arthrospira platensis cultivated in modified Zarrouk medium. Also, the work study the protein profile with molecular variations (using SDS-PAGE, Comet assay, and SCOT-PCR) in collected biomasses when compared with control (cyanobacteria cultivated in Zarrouk medium). Superoxide dismutase (SOD), glutathione peroxidase (GPX), and mineral content of each treatment were also determined. The obtained Results showed that a significant increment of growth rate of A. platensis in glycinate treatments was observed especially with Cu-glycinate more than control medium. Additionally, T11 has high O.D. than other chelated minerals but control medium had the highest O.D. than LW-chelated minerals. All A. platensis treated with the glycine-chelates possessed both conserved and additional proteins in their SDS-PAGE banding patterns. Moreover, A. platensis treated by chelated minerals with leather waste hydrolysate induced high discrimination than their analogues chelated with glycine. Six ScoT primers were applied and produced 323 amplicons with an average of 68% polymorphism/primer. SDS and Scot dendrogram revealed that among all treatments, control and Mg-glycine-chelated treatment were closely related. All A. platensis samples treated by chelated minerals with leather waste hydrolysate possessed more polymorphic bands than monomorphic ones (either as proteins or DNA), despite that no significant DNA damage (as % tDNA) was detected on A. platensis treated with either chelated treatment.

Towards sustainable aquaculture systems: Biological and environmental impact of replacing fishmeal with Arthrospira platensis(Nordstedt) (spirulina)

Sustainable fish food production is crucial for aquaculture. Microalgae, such as spirulina (Arthrospira platensis), can supplement diet antioxidants or replace expensive fishmeal with high-quality proteins. In this study, we tested fish growth and wellbeing by feeding fish on a diet in which 5% of fishmeal was replaced by spirulina (SP5 diet). The low level of spirulina in the diet was intended as supplementation and was effective in ameliorating the redox state of a model fish species (juvenile Koi Carp, Cyprinus carpio L.) in a preliminary lab protocol in a six-week trial. When compared with both the control diet (no Spirulina) and a diet containing 30% spirulina replacing fishmeal (SP30 diet), SP5 was able to reduce the muscle levels of reactive oxygen species (ROS), oxidative damage, and susceptibility to oxidative stress, while increasing glutathione reductase and peroxidase activity. However, high production costs and impacts still limit the use of spirulina in fish diet. Recent studies focused on growing spirulina on urban or agro-industrial wastewater, with appropriate profiles for the alga growth. Therefore, in a circular economy context, a possibility still to be tested and exploited is feeding farmed fish with spirulina produced on output wastewater recirculated back from the same farming plant. Life Cycle Assessment (LCA) was applied to estimate the sustainability of such “circular” fish farming. The LCA ReCiPe Midpoint (H) impact assessment method was used. Firstly, the LCA environmental impacts associated with the production of spirulina grown on aquaculture wastewater as well as on the standard culture medium (Zarrouk medium) were assessed and compared by means of a “gate to gate” analysis. Then, the LCA impacts of an SP5 diet for fish, in which spirulina grown on aquaculture wastewater was used to replace 5% fishmeal (SP5ww), were compared to the diet containing spirulina grown on a standard medium (SP5st) and that one without spirulina (control diet). Results indicated that SP5ww was significantly less impacting, by avoiding the treatment and disposal of wastewater and the need for the highly impacting standard culture medium. In conclusion, the proposed approach for using spirulina in aquaculture represents a valid solution for aquaculture circular economy scenario while at the same time improving fish welfare.

An Applied Research of the Recycled Economic Model for Spirulina Algae’s Cultivation from Ion-Life Alkaline Water and 〖CO〗_2 Gas’s Boiler

This paper presents an investigation of Spirulina algae (S. platensis) cultivation from the research and application of the circular economy model for green production by combining Ion-Life alkaline water and the gas emitted from the combustion of rice husk. This circular economy model for green production is applied in using the optimal pH values and the in which S. platensis is much easier for using. The cost of prepared medium for S. platensis cultivation from the Ion-Life alkaline water is minimized thanks to the simplex algorithm. From this algorithm, the cost prepared medium for S. platensis cultivation from the Ion-Life alkaline water can be reduced approximately 71.86 VND/liter when comparing to the Zarrouk medium (nearly equal to 3.71 % of the cost for cultivation from the Zarrouk medium). Comparing the improved medium from Ion-Life alkaline water with the Zarrouk medium for cultivating S.platensis alge are at the same conditions as the temperature from 26 ¸ 40oC and pH value from 8.6 ¸ 10.6. During the first eight days of cultivation in improved medium from Ion-Life alkaline water, the concentration of biomass increases from 0.044 to 0.93 g/L. During the next eight days, the pH values are controlled to be from 8.5 to 9.5, which is suitable for Spirulina algae since feeding the gas from the combustion of rice husk with amount of 7.6 % with the 30 minutes a day. Finding a technology that blows from smoke of boiler to make the effect of stirring the environment for achieving objectives. First, it helps to add carbon-nutrient source in the form of . Second, it helps to maintain the pH of environment in the optimal range of 8.5-9.7. As a result, the biomass concentration increases to 1.4 g/L, while this value is 1.23 g/L in the case non-using from smoke of boiler. On the basis of the obtained results, it is basic to calculate equipment and to build a technology process for the green production of cultivation of Spirulina algae from by using the molecules emitted from the combustion of biomass combining alkaline water ion-life can be applied practically.

Production of Natural and Functional Pigments in Arthrospira (Spirulina) platensis cultivated in Laboratory Conditions

In this study, Arthrospira (Spirulina) platensis was cultivated under laboratory conditions at 30 ± 1 °C and 80 µmol.m-²s-1 illumination. Intensive cultivation of Arthrospira (Spirulina) platensis was carried out in 250 mL, 500 mL and 2 L flasks, and 10 L and 20 L carboys. Zarrouk Medium was used as a nutrient medium. Constant aeration also applied in the 2 L flasks and the carboys. According to the optical density results, continually increase in the biomass yields of Arthrospira (Spirulina) platensis observed until the 24th day of the cultivation period. During the experiment, water temperature was recorded as 29.89 ± 0.45 °C, PH 10.88 ± 0.87, oxygen level of 10.18 ± 2.67 mg/L. Arthrospira (Spirulina) platensis has a wide range of pigments, including chlorophyll a, total carotenoids and phycobiliproteins (protein-rich phycocyanin and phycoerythrin). The primary potential of these pigments seems to be their use as natural dyes, but a growing number of studies have also shown that the functional properties of these pigments related to health benefits and wide pharmaceutical applications. During the cultivation of Arthrospira (Spirulina) platensis, chlorophyll a, total carotene, phycocyanin and phycoerythrin production were determined daily by using spectrophotometric methods. The study results showed that the amount of chlorophyll a increased until the 29th day when the amount of β carotene increased until the 14th day. The highest chlorophyll a was 5.46 ± 0.57 mg/gon the 22nd day, the highest total carotene was 1.82 ± 0.25 mg/g on the 7th day. On the 14th day of the experiment, the amount of phycocyanin was 172.85 ± 7.35 mg/g and the amount of phycoerythrin was 75.54 ± 4.98 mg/g.

Utilization of anaerobically digested dairy manure wastewater for Spirulina maxima cultivation

Microalgae have attracted the attention of scientists as microalgae have been considered as having higher productivities than terrestrial plants. Microalgae can be used to produce several valuable commodities such as bioenergy, feed, and food. Combining the growth medium with wastewater can enhance the economic feasibility of microalgae-based products. In this research, Spirulina maxima were cultivated using bioslurry from anaerobically digested dairy manure wastewater (ADDMW) at concentrations 0, 50, and 100 %. The growth curve was monitored by measuring the dry weight of microalgae every three days. The results showed that the S. maxima growth in ADDMW showed no difference from S. maxima growth in Zarrouk medium (2.090 g L-1 and 1.933 g L-1, respectively). Phycocyanin, one of the primary pigments of S. maxima, was determined to evaluate the effect of wastewater medium on phycocyanin production. The phycocyanin content of S. maxima in 0, 50, and 100 % wastewater showed no difference (58.67, 56.51, and 54.67 mg L-1 culture, respectively). This study provides an insight into the potential use of ADDMW as a substitute of growth medium of S. maxima as it supported the growth and phycocyanin production, with the result similar to when using the commercial medium.

Earthenware-based biofilter configuration for Spirulina cultivation on nutrients recycled from food-industry waste streams: A preliminary study

This study integrates an earthenware-based biofilter into photobioreactors (PBR), to allow Spirulina growth on organic nutrient sources. The earthenware acted as permeable membrane, enabling the bio-oxidation of soluble organics and the diffusion of mineralised ions to the photobioreactor. When fed with lactic acid fermentation effluents (organic loading rates of 11.1 mg-COD L−1PBR d−1 and 1.7 mg-Total-N L−1PBR d−1), Spirulina growth rate (19.4 mgdry mass L−1 d−1) was up to the mark with respect to a control with Zarrouk medium. However, the protein content was of 34% w/wDM (as compared to 57% in the control), likely due to insufficient mineral-N supply under the tested system-configuration. The dissolved photosynthetic oxygen established a redox potential gradient (300–400 mV) across the membrane, acting as an electron sink towards consistent COD removal rates (9.0 ± 0.7 mg-COD L−1 d−1). Configurations with higher biofilter/photobioreactor volume ratios should be tested, to improve nitrogen supply rates.

Isolation and molecular characterization of nutritionally potent Arthrospira maxima from Indian paddy field

Arthrospira maxima (A. maxima) is a cyanobacterium renowned for its usage as food and feed supplements as a potential source of functional ingredients for developing nutraceutical foods of natural origin. The Indian paddy fields, which can naturally produce eco-friendly cyanobacterial mats soon after receiving monsoon rain, were studied for isolation and molecular confirmation of Arthrospira and exploration of its nutritional profile. First, the collected cyanobacterial mat was processed for isolation of pure culture. After that, axenic culture was maintained in Zarrouk's medium at 27 ± 2 °C under the photosynthetically active radiation (PAR) of 75 μmol photon m−2 s−1 with a 16/8 h of light/dark period in laboratory condition. Morphologically proven pure culture of A. maxima was subsequently analyzed for its genomic stability using Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR) and confirmed by targeting 16S ribosomal RNA partial gene sequencing.Further confirmed and pure A. maxima extract was processed to find out its nutraceutical values (amino acids, fatty acid, vitamin and chlorophyll content) by using High-performance liquid chromatography (HPLC) and Gas chromatograph (GC) technique. Results showed that identified strain was confirmed as A. maxima, and its partial gene sequences had been submitted to NCBI to get a unique accession number (GenBank: KM407008.1.). The study explores the new strain of A. maxima as an habitant from the Indian paddy field; it may be considered a potential candidate for industrial biomass production at a large scale.

Pengaruh Variasi Konsentrasi NaNO3 pada Medium Raoof terhadap Kultivasi Spirulina Platensis

Nutrition is one of the factors that affect the growth of Spirulina platensis. The cultivation medium proposed by Raoof is a modified version of Zarrouk medium. Raoof medium requires less nutrients than Zarrouk medium but the biomass produced is almost the same. This study was conducted to vary the concentration of NaNO3 of 0.5; 1.5; 2.5; 3.5 g/L in Raoof medium to study its effect on growth and biomass composition of S. platensis. At each concentration of NaNO3 of 0.5; 1.5; 2.5; 3.5 g/L obtained the highest biomass concentration of 0.6425; 0.6455; 0.6745; 0,5193 g/L on days 12, 12, 12, 10. Concentration of NaNO3 of 2.5 g/L resulted in the highest specific growth rate of 0.1371/day and the lowest double time of 5.0566 days. In general, increasing the concentration of NaNO3 from 0.5 to 2.5 g/L increased the protein content from 33.30 to 36.98%. The addition of higher NaNO3 (3.5 g/L) actually decreased the protein content to 35.52%.

Biofixation of CO2 from a power plant through large-scale cultivation of Spirulina maxima

Using microalgae for biological fixation of CO2 is an attractive option for limiting the amount of CO2 emissions from power plants. In this experiment, Spirulina maxima was successfully grown utilizing direct flue gas emitted from the Ratchaburi Electricity Generating Company Limited, Thailand. The aims of this study were to determine the optimal conditions for large-scale culturing of this alga for maximum biomass as well as CO2 abatement. The results showed that the carbon source of NaHCO3 can be reduced from standard Zarrouk medium of 16.8 down to 8 g/L, producing fresh and dry weight biomass yields of 206 and 21.57 kg, respectively, within 30 days of cultivation. The optimal initial pH was 9.0, thereby reducing the lag phase of algal growth and producing the best fresh weight yield. The natural light intensity (with CO2) prevented stressed and weakened the algal cells, resulting in extending the algal life and producing the highest yields of fresh and dry weight. The morphology of algal cells was examined following culturing at pH 9 and pH10.5. The algal cells produced at pH 9 had a helical shape of the trichome, a separate septum and thylakoids, and the vacuoles were distributed throughout the cell, while algal cells cultured in medium with an initial pH of 10.5 mostly had the straight form, with the septum and thylakoids being unclear. The maximum CO2 level used was 2.5 times base level of the CO2 (141.75 g CO2/h) produced the highest biomass of fresh and dry weights. The optimal culture for CO2 gas was the continuous culture system and using CO2 efficiently, which encouraged algal growth and produced higher biomass yields than those from the batch culture system. There was no significant difference in nutritional value terms for the protein and pigments contents between the algal biomass products in assay with and without CO2 Furthermore, there was no metal contamination in algal biomass. The results indicate that the use of waste CO2 from a power plant can be successfully used for large-scale Spirulina production.

Sugarcane Molasses as a Cost-effective Carbon Source on Arthrospira maxima Growth by Taguchi Technique

In this research, a new cost-effective carbon source of medium was provided in terms of high-efficiency growth from Arthrospira maxima. Sugarcane molasses was used in two different modes (alternative and additive) at four different concentrations (0, 0.5, 1.0 and 1.5 gL-1) to determine the effect of new carbon source versus its standard carbon source of Zarrouk’s medium (NaHCO3). The experimental results were analyzed by Taguchi L8 method as a statistical technique. The highest biomass production obtained when sugarcane molasses was added as an alternative source, which was 5.31 times higher than the usual Zarrouk's media. Furthermore, final biomass concentration increased with increasing molasses concentration from 0 to 1.5 gL-1 in this group. At highest concentration, phycocyanin (at 0.11 and 0.12 gL-1), allophycocyanin (at 0.13 and 0.12 gL-1), carotenoids (at 2340 and 2535 mgL-1), chlorophyll a (at 23.83 and 24.83 mgL-1), and chlorophyll b (at 0.343 and 2.99 mgL-1) obtained when molasses were added as an additive and alternative sources, respectively. Finally, the replacement of standard carbon sources of medium with sugarcane molasses had the potential possibility in order to reduce the production costs of Arthrospira maxima growth.